Authorities in Myanmar say they have detained a dozen rioters involved in weekend religious violence in the country's north west.

The attack on Muslims in Htan Gone village, in the town of Kantbalu, happened after rumours that a Muslim man had tried to sexually assault a Buddhist woman.

In the two days of violence, led by a thousand strong Buddhist mob, 42 homes and 15 shops were burnt, leaving hundreds of Muslims homeless.

Hundreds made homeless in the latest eruption of violence are sheltering in a school as authorities make arrangement to open up camps to house them.

This is the first anti Muslim violence in this region and it shows that this sectarian unrest is set to widen.

Since clashes between Buddhists and the Rohingya Muslim minority broke out in the west of the country last year, anti-Muslim anger has fanned across the country with violence in in central Meikhtila in March and north-eastern Lashio in May.

Toe Zaw Latt, bureau chief for the Democratic Voice of Burma, based in Yangon, says unlike the Rohingyas of Arakan State, the Muslims in Lashio, Meikhtila and now Htan Gone have lived here for centuries and have never been seen as illegal immigrants from Bangladesh.

"There is no question about migration - they've been there for a long time," he said.

Since the start of sectarian violence in June last year, some 250 people, mostly Muslims, have been killed and another 140,000 left homeless.

Much of the anti-Muslim sentiment is being managed and fuelled by the ultra-nationalist, 969 Movement, which calls for Buddhists to boycott Muslim businesses and avoid interfaith marriages.

Toe Zaw Latt says Muslims who have for centuries co-existed peacefully with the majority Buddhists are now being portrayed as troublemakers and the extremists have fertile ground to work on.

"The people have been silent for a long time - they were not allowed to express even their feelings. So at the moment there is religious freedom so that especially in the rural areas, where there are majority Buddhists, it is very easy to organise extremist beliefs," he said.

Power divisions mean no action to tackle sectarian violence

Rights groups have accused authorities of being unable or unwilling to contain the unrest.

Even the UN special rapporteur, Tomas Quintana, experienced fear during his recent visit when an angry mob attacked his car while police looked on.

Toe Zaw Latt says power fragmentation is the root cause for much of the inaction or inability to contain unrest. He says unlike in the past, when power reigned supreme in the hands of one man - the regime chief - now, there are three centres of power.

"One is with the President's office, one is with the Parliament, one is with the Army - so their power centres are being fragmented after three years with this new Administration," he said.

Toe Zaw says that in the past, the Army has takes charge but now it's hard to know who is responsible for sectarian violence - whether it's Ministry of the Interior or Religious Affairs or local government.

With sectarian violence spreading right across the country, some fear if left unchecked, it could lead to potential crimes against humanity or genocide and to a culture of impunity.

Toe Zaw Latt says the problem cannot be solved by the authorities alone - it needs a strong civil society which is still lagging.